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		<h1><a href="../index.html"><img src="../docs-assets/Inform.png" height=72> </a></h1>
<ul><li><a href="../index.html">home</a></li>
</ul><h2>Compiler</h2><ul>
<li><a href="../structure.html">structure</a></li>
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<li><a href="../inform7n.html">inform7</a></li>
<li><a href="../intern.html">inter</a></li>
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<li><a href="../inblorbn.html">inblorb</a></li>
<li><a href="../inform6.html">inform6</a></li>
<li><a href="../inpolicyn.html">inpolicy</a></li>
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<li><a href="../extensions.html">extensions</a></li>
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<li><a href="https://github.com/ganelson/inform"><img src="../docs-assets/github.png" height=0> github</a></li>
</ul><h2>Related Projects</h2><ul>
<li><a href="https://github.com/ganelson/inweb"><img src="../docs-assets/github.png" height=0> inweb</a></li>
<li><a href="https://github.com/ganelson/intest"><img src="../docs-assets/github.png" height=0> intest</a></li>
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    <ul class="crumbs"><li><a href="../index.html">Home</a></li><li><a href="../intern.html">Inter Modules</a></li><li><a href="index.html">final</a></li><li><a href="index.html#P">Preliminaries</a></li><li><b>What This Module Does</b></li></ul></div>
<p class="purpose">An overview of the final module's role and abilities.</p>

<ul class="toc"><li><a href="P-wtmd.html#SP1">&#167;1. Prerequisites</a></li><li><a href="P-wtmd.html#SP2">&#167;2. Finally final</a></li></ul><hr class="tocbar">

<p class="commentary firstcommentary"><a id="SP1" class="paragraph-anchor"></a><b>&#167;1. Prerequisites.</b>The final module is a part of the Inform compiler toolset. It is
presented as a literate program or "web". Before diving in:
</p>

<ul class="items"><li>(a) It helps to have some experience of reading webs: see <a href="../inweb/index.html" class="internal">inweb</a> for more.
</li><li>(b) The module is written in C, in fact ANSI C99, but this is disguised by the
fact that it uses some extension syntaxes provided by the <a href="../inweb/index.html" class="internal">inweb</a> literate
programming tool, making it a dialect of C called InC. See <a href="../inweb/index.html" class="internal">inweb</a> for
full details, but essentially: it's C without predeclarations or header files,
and where functions have names like <span class="extract"><span class="extract-syntax">Tags::add_by_name</span></span> rather than just <span class="extract"><span class="extract-syntax">add_by_name</span></span>.
</li><li>(c) This module uses other modules drawn from the compiler (see <a href="../structure.html" class="internal">structure</a>), and also
uses a module of utility functions called <a href="../foundation/index.html" class="internal">foundation</a>.
For more, see <a href="../foundation/P-abgtf.html" class="internal">A Brief Guide to Foundation (in foundation)</a>.
</li></ul>
<p class="commentary firstcommentary"><a id="SP2" class="paragraph-anchor"></a><b>&#167;2. Finally final.</b>The final module is aptly named, in that it is the very last stage in compiling
an Inform project. Everything up to this module has been generating a tree of
Inter code, which is (to a large extent) an abstract, general-purpose description
of a program. We finally turn that into an Inform 6 program, or a C program,
or some other concrete expression of that program.
</p>

<p class="commentary">This module has a very simple interface to the rest of the tool chain: it
simply provides a single Inter pipeline stage called <span class="extract"><span class="extract-syntax">generate</span></span>. See
<a href="2-cg.html#SP1" class="internal">CodeGen::create_pipeline_stage</a>. When this stage is reached, the function
<a href="2-cg.html#SP1" class="internal">CodeGen::run_pipeline_stage</a> is run. This then creates a <a href="2-cg.html#SP2" class="internal">code_generation</a>
object, which holds all the temporary storage and configuration details for a
single act of code-generation. The most important of those details is the
choice of which <a href="2-cg2.html#SP1" class="internal">code_generator</a> to use &mdash; see below.
</p>

<p class="commentary firstcommentary"><a id="SP3" class="paragraph-anchor"></a><b>&#167;3. </b>The module creates a small number of //code_generator//s, one for each
possible output format. For example, <a href="4-fi6.html#SP1" class="internal">I6Target::create_generator</a> creates
one which represents "output Inform 6 code, please"; <a href="5-fnc.html#SP1" class="internal">CTarget::create_generator</a>
creates one for "output ANSI C-99 code, please".
</p>

<p class="commentary">If you are considering adding a new output format, say for JavaScript or Python,
that should be done by adding a new <a href="2-cg2.html#SP1" class="internal">code_generator</a>. Although the default
generator is the Inform 6 one, that is in some ways misleadingly simple in
design because Inter, our intermediate format, was originally designed as a
sort of abstract paraphrase of Inform 6 &mdash; which means that it's quite easy
to turn Inter to I6. The C code generator is a much better example of the real
issues likely to present themselves. So reading through the chapter on C is
probably the best way to get an idea of the task.
</p>

<p class="commentary firstcommentary"><a id="SP4" class="paragraph-anchor"></a><b>&#167;4. </b>It seems likely that many if not most of the formats we will ever need to
generate will be procedural programming languages of the sort usually called
C-like, and we want to avoid duplicated effort. A generic algorithm called
<a href="2-vnl.html" class="internal">Vanilla</a> is therefore provided: a generator can, if it wishes, make use of
this to simplify its work, and both our C and Inform 6 generators do so.
</p>

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